package com.itheima.reggie.filter;

import com.alibaba.fastjson.JSON;
import com.itheima.reggie.common.BaseContext;
import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Slf4j
@WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")
public class LoginCheckFilter implements Filter {
    //路径匹配器，支持通配符
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) servletRequest;
        HttpServletResponse resp = (HttpServletResponse) servletResponse;

        //    A. 获取本次请求的URI
        String requestURI = req.getRequestURI();
        log.info("拦截到请求：{}", requestURI);

        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**",
                "/common/**",
                "/user/login",
                "/user/sendMsg",
                //Swagger及Knife4j相关的静态资源
                "/doc.html",
                "/webjars/**",
                "/swagger-resources",
                "/v2/api-docs"
        };

        //B. 判断本次请求, 是否需要登录, 才可以访问
        boolean check = checkIsEquals(urls, requestURI);

        //C. 如果不需要，则直接放行
        if (check) {
            log.info("本次请求{}不需要处理", requestURI);
            filterChain.doFilter(req, resp);
            return;
        }
        //D. 判断登录状态，如果已登录，则直接放行
        if (req.getSession().getAttribute("employee") != null) {
            log.info("用户已登录，用户id为：{}", req.getSession().getAttribute("employee"));
            Long empId = (Long) req.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empId);
            filterChain.doFilter(req, resp);
            return;
        }

        if (req.getSession().getAttribute("user") != null) {
            log.info("用户已登录，用户id为：{}", req.getSession().getAttribute("user"));
            Long userId = (Long) req.getSession().getAttribute("user");
            BaseContext.setCurrentId(userId);
            filterChain.doFilter(req, resp);
            return;
        }
        //E. 如果未登录, 则返回未登录结果
        log.info("用户未登录");
        //通过输出流方式向客户端页面响应数据
        resp.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;

    }

    /**
     * 路径匹配，检查本次请求是否需要放行
     *
     * @param urls
     * @param requestURI
     * @return
     */
    private boolean checkIsEquals(String[] urls, String requestURI) {
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if (match) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void destroy() {
        BaseContext.removeCurrentId();
    }
}